Tire constructions generally include a sidewall insert variously for support of the tire sidewall. In the case of conventional tires, an apex may be included to provide support in the sidewall near the bead. In the case of runflat tires, one or more runflat inserts may be included in the sidewall to provide support in the event of a tire deflation.
These sidewall inserts, both apexes and runflat inserts, are typically of nonuniform cross-section with a relatively thick section and one or more relatively thin sections. Cure of the inserts is problematic owing to the uneven heat transfer in the thick and thin sections. It would then be advantageous to have a more evenly cured sidewall insert.